Jebcore:- If Jebediah Kerman dies, you lost the game.- Jeb can't be left on Kerbin - if he's on the ground, he should be sent off in the same game day.- Jeb being in a foreign celestial body or derelict ship for over a year counts as dying.

Kerblocke:- One rocket design per science tier. - You must unlock all the tech on the next tier before you can design a new one.- If a rocket explodes, that rocket design can no longer be used.